A device for measuring an internal resistance of a laminated type battery with power supplied to a load from the laminated type battery is proposed in WO2012077450.
This measuring device outputs the same alternating currents to a positive electrode terminal and a negative electrode terminal of the laminated type battery such that no current leaks to a load side connected to the laminated type battery. Then, an amplitude of the alternating current output to each electrode is adjusted such that an alternating-current potential difference on a positive electrode side obtained by subtracting a potential of an intermediate-point terminal located between the positive electrode terminal and the negative electrode terminal from a potential of the positive electrode terminal of the laminated type battery and an alternating-current potential difference on a negative electrode side obtained by subtracting the potential of the intermediate-point terminal from a potential of the negative electrode terminal coincide. Then, the internal resistance of the laminated type battery is measured on the basis of the adjusted alternating currents and potential differences.